Introduction to Programming

Doman’s Lecture

CSCI101

A deep understanding of programming, in particularthe notions of successive decomposition as a mode ofanalysis and debugging of trial solutions, results insignificant educational benefits in many domains ofdiscourse, including those unrelated to computers andinformation technology per se.

(Seymour Papert, in "Mindstorms")

What is programming?

Programming is a creative process done byprogrammers to instruct a computer on how to do atask. (http://cplus.about.com)

Writing an original program that performs a particulartask that meets all stated constraints (Think Like aProgrammer, V.Anton Spraul, No Starch Press, Inc. 2012)

What is programming?

A lot of this lecture is taken from the book:

Think Like a Programmer,

By V.Anton Spraul,

No Starch Press, Inc. 2012

What is programming?

Method or interface to do this:

PROGRAMMING LANGUAGES

Example: Java:

Public class helloWorld {

Public static void main ( ) {

system.out.println(“Hello World”)

}

Instruct a computer

Example: C++

#include<iostream>

using namespace std;

int main()

{

cout << “Hello World” << endl;

}

Instruct a computer

Example: html

<html>

<body>

<p> Hello World </p>

</body>

</html>

Instruct a computer

GAMEMAKER

Drag and drop structured language

Uses icons, text…. Made to be easier than any ofthe previous languages.

Instruct a computer

Programming is a creative process done byprogrammers to instruct a computer on how to do atask. (http://cplus.about.com)

What is programming?

Programming is a creative process done byprogrammers to instruct a computer on how to do atask. (http://cplus.about.com)

Writing an original program that performs a particulartask that meets all stated constraints (Think Like aProgrammer, V.Anton Spraul, No Starch Press, Inc. 2012)

What is programming?

Puzzles

Problem solving

What is programming?

Your car has blue smoke coming from the tailpipe, isidling roughly and has lost fuel efficiency.

How do you solve it?

Problem Solving

Unbreakable rules about problems or the way inwhich problems must be solved.

Car problem constraints:

Cost of repair

How long before you need it fixed

No new tools be purchases

Constraints

Programming language

Platform

Performance

Memory footprint

User/customer specific constraints

Design constraints.

Common Programming Constraints

Figure out the steps to take to solve the problem

Be able to list the steps

Be able to repeat the steps

You can NOT change the rules (constraints) to getsomething solved!

Problem solving

PROBLEM: HOW TO CROSS THE RIVER?

A farmer with a fox, a goose and a sack of cornneeds to cross a river. The farmer has a rowboat,but there is only room for the farmer and one of histhree items. Unfortunately, both the fox and thegoose are hungry. The fox cannot be left alonewith the goose; the goose cannot be left alonewith the grain. How does the farmer geteverything across the river?

Puzzle: Fox, goose, grain

Constraints

Only one item at a time in the boat

Can’t leave fox with goose

Can’t leave goose with grain

Operations

Carry the fox to the far side of the river

Carry the goose to the far side of the river

Carry the grain to the far side of the river

Puzzle: Fox, goose, grain

Puzzle: Fox, goose, grain

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\YHB28N3D\MP900201746[1].jpg$

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\HY3OU23Y\MC900441392[1].wmf$

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\EF10C8ZR\MC900083946[1].wmf$

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\YHB28N3D\MC900290567[1].wmf$

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\K8HK0RLE\MC900352086[1].wmf$

Abstract the problem

Be more general in describing the way we will solvethe problem

Concept: Variable

Items are fox, goose or grain

Let item vary between fox, goose or grain

Rephrase the problem

Constraints

Only one item at a time in the boat

Can’t leave item(fox) with item(goose)

Can’t leave item(goose) with item(grain)

Operations

 Row the boat from one shore to the other

If the boat is empty, load an item on the boat

If the boat is full, take the item off the boat

Puzzle: Fox, goose, grain

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\YHB28N3D\MP900201746[1].jpg$

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\K8HK0RLE\MC900352086[1].wmf$

Puzzle: Fox, goose, grain

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\HY3OU23Y\MC900441392[1].wmf$

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\EF10C8ZR\MC900083946[1].wmf$

$C:\Users\doman\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\YHB28N3D\MC900290567[1].wmf$

Puzzle: Sudoku

Constraints



Techniques

 Start with the easiest

Try something…… be prepared to change if it doesn’t work.

Try something else

Puzzle: Soduko

PROBLEM: THE SLIDING EIGHT

A 3x3 grid is filled with eight tiles, numbered 1through 8 with one empty space. The grid isjumbled. A tile can be slid into an adjacentempty space, leaving its previous locationempty. Slide the tiles so that they are innumerical order

Puzzle: Sliding Tile

Puzzle: Sliding TileSolution

Puzzle: Sliding Tile

Technique: the train

A circuit of tile positions that include an empty slotforms a train of tiles that can be rotated anywherealong the circuit, preserving the relative order of thetiles.

Puzzle: Sliding Tile